The detection of wheel speed is important in a variety of vehicles, from aircraft to automobiles. Such devices provide wheel speed feedback to other system components for enhanced vehicle control. For example, in aircraft, wheel speed information may be used in components that control braking. Wheel speed information may also be beneficial for the operation of certain anti-skid systems as well.
Conventional aircraft wheel speed sensors often use a gear assembly disposed in an axle. The gear assembly is coupled with a blade that is in mechanical communication with an aircraft wheel or hubcap. For example, the blade may be coupled to a hubcap with a spring clip and/or a screw. The motion of the blade drives the gear assembly. The gear assembly comprises an inside gear and an outside gear coupled with magnetic components such that the gear assembly functions as an electrical generator. Electrical components are typically coupled to the gear assembly to monitor output voltages. These components may then determine wheel speed based upon this information. Thus, the blade and clip are subject to mechanical wear and need to be monitored for required maintenance, mechanical failures, and potential misalignments. Such devices may also be prone to misalignment and/or other unintended spatial displacements that may affect performance. Further, such a component cannot detect a speed of 0 because there is no motion to drive the gear assembly. Moreover, such conventional devices typically lose accuracy at low speeds (e.g., below 8 knots). In addition, as conventional means typically rely on measuring “pulse” after a predetermined rotational distance, very low speeds are not able to be detected. Accordingly, there is a need for more accurate measurement of wheel speed at low speeds and very low speeds.
In addition to wheel speed, the monitoring of tire pressure is also important in a variety of vehicles. Proper tire pressure enhances efficiency and safety of a vehicle, and improper tire pressure may require repairs.
Conventional tire pressure monitors often use a wireless enabled pressure reading device in fluid communication with a tire. The tire pressure monitor reads tire pressure by way of its fluid communication channel with the tire. The monitor then transmits pressure information wirelessly (e.g., via RF signal) to another component for monitoring. However, it may be difficult to power such a system, and the RF signal may be disturbed by other RF signals produced in an aircraft.
These and other conventional systems for tire pressure monitoring and/or wheel speed detecting tend to be unnecessarily complex, costly, and prone to mechanical failures or wear.
Accordingly, there is a need for systems for tire pressure monitoring and/or wheel speed detecting that address at least one of these issues. For example, there is a need for non-contact or reduced contact systems and methods for tire pressure monitoring and/or wheel speed detecting.